It is known to equip vehicle seats with a pneumatic suspension system which includes, among other things, at least one air spring and a control device which carries out an automatic level adjustment as a function of the weight loading a seat part of the vehicle seat. By way of example, when the seat is occupied by a driver of substantial weight, more air pressure is introduced into an air spring arranged within a base frame below the seat part. This typically produces the desired suspension effect with equal spring travel both in the upward and downward direction. By contrast, if the seat is occupied by a person of relatively insubstantial weight, air is discharged from the air spring within the suspension system in order to avoid too high an arrangement of the seat for this person and thus too short a spring travel in the upward direction.
Such suspension systems often cannot distinguish between the state of an occupied seat and the state of an unoccupied seat. As a result, the unoccupied seat state leads to the situation in which previous vehicle seats are set to a level as a function of their weight, which is primarily determined by the seat part, a backrest and parts of the base frame. Such a leveling of the vehicle seat has the result that, following previous seat occupancy, in the state of seat non-occupancy substantial air is unnecessarily discharged from the suspension system in order to obtain such a setting as a function of the intrinsic weight of the seat. This leads to an unnecessary waste of the air present in the suspension system and in particular in the air spring, which must be re-introduced, for example by means of a compressor.
Accordingly, there is a need for a control device configured to control a pneumatic suspension system of a vehicle seat spring-mounted to a vehicle body part in which the air discharged from the suspension system is controlled as a function of seat occupancy.